The Associated Press and CBSSports.com also reported that Helfrich, 39, will be named coach.

Mark Helfrich is well versed in Oregon's offense, having run it for the past four years. (AP Photo)

Oregon announced that it would have a 4 p.m. ET press conference to announce the hiring. Wide receivers coach Scott Frost is expected to be promoted to offensive coordinator.

Oregon, ranked No. 2 in the final AP Top 25, went 12-1 this season capped by a victory over Kansas State in the Fiesta Bowl.

Last year, when Kelly told his superiors that he would take the Tampa Bay Buccaneers job, the decision was made to promote Helfrich. That was brief, as Kelly changed his mind. This time, the Ducks will be making it official with Kelly leaving to coach the NFL's Philadelphia Eagles.

Helfrich is known as a good quarterbacks coach and is well-versed in Kelly’s nationally recognized offense. The philosophical and brand continuity is an important factor for the Ducks.

Helfrich coached at Boise State, Arizona State and Colorado before joining the Ducks under Kelly. Kelly inherited the job from Mike Bellotti, and Bellotti took over following Rich Brooks.

Helfrich "can finish Chip's sentences," a source told USA Today two-plus weeks ago. "He's been in that environment long enough (to succeed). It's a leap of faith, but it's very similar — I'd almost argue that it was a bigger leap (promoting) Chip than Mark."

Oregon athletic director Rob Mullens told OregonLive.com on Wednesday that he would conduct a coaching search and denied reports that Helfrich had already been selected.

Oregon conducted interviews without releasing information on candidates. Sources confirmed reports that Mullens interviewed Stanford offensive coordinator Pep Hamilton on Friday. He was at least the second candidate interviewed, according to a source.

Hamilton on Friday, however, became offensive coordinator of the Indianapolis Colts.

While defensive line coach Jerry Azzinarro followed Kelly to the Eagles, Helfrich's hiring is expected to keep much of the Ducks' staff intact, OregonLive.com reported. That includes defensive coordinator Nick Aliotti, offensive line coach Steve Greatwood, running backs coach Gary Campbell, secondary coach John Neal and linebackers coach Don Pellum.

Helfrich becomes the third consecutive offensive coordinator Oregon has promoted to head coach. Bellotti took over following Rich Brooks' departure.

Not much is expected to change under Helfrich, who is himself following Kelly's "Next Man In" philosophy.

As offensive coordinator, Helfrich has been in charge of Oregon's quarterbacks, guiding both Darron Thomas and redshirt freshman Marcus Mariota.

This season Mariota set the team's single-season record with 38 touchdowns (32 passing, 5 rushing, 1 receiving), surpassing the previous mark of 36 held by Thomas (2011) and Akili Smith (1998).

The first freshman named to the Pac-12's all-conference first team in 23 years, Mariota passed for 2,739 yards, completing a school-record 68.5 percent of his passes. He had 3,429 yards of total offense, second only to Smith's 3,947 in 1998.

Thomas, his predecessor, passed for 2,761 yards and a school-record 33 passing touchdowns his junior season last season despite missing a game because of an injury. He left school with a year of eligibility remaining in hopes of playing in the NFL but went undrafted.

Frost, 38, came to Oregon in 2009 after serving as an assistant at Northern Iowa. He played seven seasons in the NFL after leading the Huskers to the national title over Tennessee in the 1997 Orange Bowl.